Shima's father is portrayed as a man whose overcritical demeanor fueled familial discord, culminating in a divorce marked by his and his wife’s mutual fixation on personal grievances and unmet expectations. Their failure to prioritize their son’s emotional needs prompted Shima’s grandfather to intervene, legally assuming custody of the child to protect him from their neglect. The grandfather attributes this critical disposition to the father’s inherent self-centeredness, condemning both parents for consistently elevating their desires above their son’s welfare. While the character bears the enigmatic title of "Undertaker," its significance remains unexplained in existing materials. No documented accounts address the character’s involvement in alternate narratives or spin-offs, nor expand upon relationships beyond the divorce’s direct influence on Shima’s upbringing.